Catalyst composition consisting essentially of iron compounds, organometallic compounds and nitrogen compounds

ABSTRACT

Method of polymerizing conjugated diolefinic monomers containing from 4 to about 12 carbon atoms to high molecular weight polymers by bringing said monomers into contact with a catalyst system consisting of (1) an iron-containing compound, (2) an organometallic reducing agent from Groups I and III of the Periodic Table, and (3) a nitrogen-containing ligand.

This is a continuation of application Ser. No. 744,013 filed Nov. 22,1976, now abandoned which is a division of Ser. No. 526,345, filed Nov.22, 1974, now U.S. Pat. No. 4,048,418.

This invention is directed to a method of polymerization of conjugateddiolefins containing from 4 to about 12 carbon atoms to formhomopolymers and copolymers. It is also directed to the catalyst systemsused to prepare these polymers. These polymers have utility in tires andother rubber products. Properties of homopolymers range from rubbers toplastics. By random copolymerizing two monomers, it frequently ispossible to break up the crystalline (plastic-like) homopolymers andproduce copolymers having elastic properties, high tensile strength andimproved green strength.

More specifically, this invention is directed to the use of ironcontaining compounds in conjunction with nitrogen containing ligands aseffective catalysts for polymerization of conjugated diolefins to highmolecular weight polymers.

A variety of compounds are utilized as catalysts to convert monomericmaterials which are capable of being polymerized into high molecularweight polymers. However, the specific types of catalyst componentsutilized in the instant invention have heretofore not been disclosed.

The catalyst system used in the instant application has severaladvantages over some of the well-known prior art catalyst systemsutilizing other transition metals.

Some catalyst systems utilizing nickel as one of its components canpolymerize a monomer such as butadiene but cannot effectively polymerizeisoprene or copolymerize isoprene and piperylene. The particularcatalyst system of the instant invention has a rather broad generalrange of uses. It can polymerize and copolymerize a variety ofconjugated diolefins and can also polymerize certain isomeric monomerforms that some of the prior art catalyst systems can not successfullypolymerize. The advantages of the present catalyst system are that it isa general purpose catalyst system capable of polymerizing a variety ofmonomers to give polymers with a high degree of stereo regularity, yetable to polymerize to high yields without excessively longpolymerization times to give this wide range of polymers with variedphysical characteristics. It can also tolerate much higher levels ofseveral frequent impurities that are present in these types of solutionpolymerization systems, i.e. acetylenes, olefins, cyclopentene andcyclopentadiene.

According to the invention, conjugated diolefinic monomers containingfrom 4 to about 12 carbon atoms are polymerized to high molecular weightpolymers by bringing said monomers into contact with a catalyst systemconsisting of (1) an iron containing compound, (2) an organometallicreducing agent from Groups I and III of the Periodic Table and (3) anitrogen containing ligand.

The iron containing compounds of this invention are those which arecapable of being reduced. Iron compounds which can be utilized in thisinvention are salts of carboxylic acids, organic complex compounds ofiron, salts of inorganic acids and iron carbonyls. Representative ofthese iron compounds are ferric oxalate, ferric hexanoate, ferricoctanoate, ferric decanoate, ferric stearate, ferric naphthenate,ferrous acetylacetonate, ferric acetylacetonate,ferric-1-ethoxy-1,3-butanedionate, ferrous dimethyl glyoxime, ferricchloride, ferrous chloride, ferric bromide, ferric fluoride, ferricphosphate, ferrous sulfate, iron tetracarbonyl, iron pentacarbonyl andiron nonacarbonyl. Iron compounds which are soluble in hydrocarbons arepreferred. The preferred representatives of these iron compounds areiron octanoate, iron decanoate, ferric acetylacetonate and ironnaphthenate.

The organometallic compounds useful in this invention areorganocompounds of such metals as aluminum, lithium and sodium. By theterm "organometallic" is meant alkyl, cycloalkyl, aryl, arylalkyl,alkaryl radicals are attached to the metal to form the organocompound ofthe particular metal.

Of the organometallic compounds useful in this invention, it ispreferred to use organoaluminum compounds.

By the term "organoaluminum compound" is meant a any organoaluminumcompound responding to the formula: ##STR1## in which R₁ is selectedfrom the group consisting of alkyl (including cycloalkyl), aryl,alkaryl, arylalkyl, alkoxy, hydrogen, cyano and halogen, R₂ and R₃ beingselected from the group of alkyl (including cycloalkyl), aryl, alkaryland arylalkyl. Representative of the compounds responding to the formulaset forth above are: diethylaluminum fluoride, diethylaluminum chloride,di-n-butylaluminum chloride, diisobutylaluminum chloride,dioctylaluminum chloride, diphenylaluminum chloride, diethylaluminumbromide and diethylaluminum iodide. Also included are diethylaluminumhydride, di-n-propylaluminum hydride, di-n-butylaluminum hydride,diisobutylaluminum hydride, diphenylaluminum hydride, di-p-tolylaluminumhydride, dibenzylaluminum hydride, phenyl ethylaluminum hydride,phenyl-n-propylaluminum hydride, p-tolyl ethylaluminum hydride,benzyl-n-propylaluminum hydride, and other organoaluminum hydrides. Alsoincluded are trimethylaluminum, triethylaluminum, tri-n-propylaluminum,triisopropylaluminum, tri-n-butylaluminum, triisobutylaluminum,tripentylaluminum, trihexylaluminum, tricyclohexylaluminum,trioctylaluminum, triphenylaluminum, tri-p-tolylaluminum,tribenzylaluminum, ethyl diphenylaluminum, ethyl di-p-tolylaluminum,ethyl dibenzylaluminum, diethyl phenylaluminum, diethyl p-tolylaluminum,diethyl benzylaluminum and other triorganoaluminum compounds. Alsoincluded are diethylaluminum cyanide, diethylaluminum ethoxide,diisobutylaluminum ethoxide and dipropylaluminum methoxide.Ethylaluminum dichloride and ethylaluminum sesquichloride also may beused as the organoaluminum compound.

By the term "organolithium compounds" is meant any organolithiumcompound responding to the formula R--Li where R is an alkyl, alkaryl,arylalkyl or aryl group. Representative among the compounds respondingto the formula set forth above are ethyllithium, propyllithium, n-, sec-or t-butyllithium, hexyllithium, styryllithium or phenyllithium. Theterm "organolithium compounds" also refers to catalysts responding tothe formula Li-R-R'-Li such as difunctional lithium catalysts, forexample, DiLi-1, DiLi-3 and the like, which are produced by LithiumCorporation of America.

Organosodium compounds include tetraethyl sodium aluminum and diethylsodium aluminum dihydride.

Also, by the term "organolithium aluminum compounds" is meant anycompound responding to the formula R'R"₃ LiAl where R' and R" may behydrogen, alkyl, alkaryl, or arylalkyl groups. R' and R" may or may notbe the same. Representative of these compounds are tetraethyl lithiumaluminum, n-butyl-triisobutyl lithium aluminum, tetrabutyllithiumaluminum, tetraisobutyllithium aluminum, butyl triethyl lithiumaluminum, styryl tri-normal propyl lithium aluminum, triethyl lithiumaluminum hydride and diethyl lithium aluminum dihydride.

The nitrogen containing ligand used in the practice of this inventionmust contain at least two functional groups or atoms which are capableof coordinating with the iron. One of these functional groups must be acyano group, that is, --C.tbd.N. The second functional group may be (a)another cyano group, (b) azo (--N═N--), (C) imino ##STR2## (d) vinylene##STR3## (e) mercapto (--SH), (f) hydroxyl (--OH), (g) thio (--S--) or(h) oxygen atom. There must not be more than two additional carbon atomsseparating the cyano and the second functional group. The exact natureor mechanism of the coordination of the nitrogen containing ligands withiron is not known, although it generally is hypothesized that twofunctional groups coordinate as a bidentate ligand with the iron.According to this hypothesis, and depending on the nature of thenitrogen containing ligand, it may form a four, five, six orseven-membered chelate ring with iron. For example, it probably ispossible for malononitrile to form a 6-membered ring with iron asfollows: ##STR4## It is pointed out that not all of the nitrogencontaining ligands exhibit optimum activity at equivalent mole ratio ofligand to iron. This suggests that all of the ligands probably do notchelate with iron in the same manner. For example, although it ispossible to write a ring structure for acrylonitrile chelated with iron,a planar structure involving two moles of acrylonitrile per iron atomalso is proposed: ##STR5##

As stated previously, the mechanism is not known, but it is notnecessary to know the mechanism in order to understand the presentinvention. The proposal of a mechanism of chemical reaction is notintended in any way to limit the scope of this invention. It isemphasized that each nitrogen ligand must contain at least one cyanogroup plus a second functional group; representatives of each of thesesecond functional group classes are as follows:

(a) a second cyano group: cyanogen, malononitrile, succinonitrile,methyl succinonitrile, 1,2-dicyanobenzene, 1,2-dicyanocyclobutane,tetracyanoethane, tetracyanoethylene, hexacyanoisobutylene,2,5-diamino-3,4-dicyanothiophene, 3,4-dicyanopyrrole,2,3-dicyano-2-butene, diethylaluminum cyanide and the like;

(b) azo group: azobisisobutyronitrile,2,2'-azobis-2,4-dimethylvaleronitrile, 2-t-butylazo-2-cyanopropane,2-t-butylazo-2-cyanobutane, 2-t-butylazo-2-cyano-4-methylpentane,2-t-butylazo-2-cyano-4-methoxy-4-methylpentane,1-t-butylazo-1-cyanocyclohexane, ethylenebis(4-t-butylazo-4-cyanovalerate), and 2-(t-butylazo) isobutyronitrile;

(c) imino-dicyandiamide (═cyanoguanidine), iminosuccinonitrile,diiminosuccinonitrile and the like;

(d) vinylene: fumaronitrile, maleonitrile, 1,4-dicyano-2-butene,acrylonitrile, methacrylonitrile, 2-chloroacrylonitrile,diaminomaleonitrile, 1-cyano-1-propene, 1-cyano-1,3-butadiene,1,2-dicyano-1-butene and the like;

(e) mercapto: 2-mercapto-isobutyronitrile, 2-mercapto-propionitrile;

(f) hydroxyl: acetonecyanohydrin, 2,3-dicyanohydroquinone-1,4,2-hydroxy-succinonitrile, biacetylcyanohydrin and the like;

(g) thio: butyl thiocyanate, hexyl thiocyanate, benzyl thiocyanate,phenyl thiocyanate, potassium thiocyanate and the like; and

(h) oxygen atom: potassium cyanate, 2-cyanoacetamide, 2-cyanoformamideand the like.

The catalyst system of the present invention has polymerization activityover a wide range of catalyst concentrations and catalyst ratios. Thecatalyst components interreact to form the active catalysts. As aresult, the optimum concentration for any one catalyst is very dependentupon the concentrations of each of the other catalyst components.Furthermore, while polymerization will occur over a wide range ofconcentrations and ratios, polymers having the most desirable propertiesare obtained over a narrower range.

The molar ratio of the organometallic compound when it is atriorganometallic to the iron compound, Al/Fe, can be varied from about1/1 to about 400/1; however, a more preferred range of Al/Fe is fromabout 1/1 to about 4/1. However, when the organometallic compoundcontains an alkoxy group or halide, then the molar ratio of theorganometallic compound to the iron compound, Al/Fe, can be varied fromabout 6/1 to about 25/1 and a more preferred ratio is about 12/1; andwhen the organometallic compound is an organolithium compound, then adesirable molar ratio of organometallic compound to the iron compound,Li/Fe, is about 6/1.

The molar ratio of the nitrogen ligand to the iron compound, N/Fe, canbe varied depending on which nitrogen compound is utilized; however, arange of about 0.1/1 to about 100/1 can be used, with a more preferredrange of N/Fe from about 0.3/1 to about 3/1.

The catalyst components may be charged to the polymerization system asseparate catalyst components in either a stepwise or a simultaneousmanner, sometimes called "in situ". The components also may be premixedoutside the polymerization system and the resulting blend then added tothe polymerization system. The catalyst components also may bepreformed, that is, premixed in the presence of a small amount of aconjugated diolefin, prior to being charged to the main portion of thesolution that is to be polymerized. The amount of conjugated diolefinwhich may be present during the preforming of the catalyst can rangebetween about 1:1 to about 1000:1 moles per mole of iron compound, andpreferably should be between about 4:1 and 50:1 mole ratio; or about 0.1to 5.0 percent of total amount to be polymerized.

The concentration of the catalyst employed depends on such factors aspurity, rate desired, temperature and other factors. Therefore, specificconcentrations cannot be set forth except to say that catalytic amountsare used. Polymerizations have been made using molar ratios of monomerto the iron catalyst ranging between 300:1 to 18,000:1, while thepreferred molar ratio is generally between about 600:1 and 3700:1. Somespecific concentrations and ratios which produce elastomers havingdesirable properties will be illustrated in the examples given herein toexplain the teachings of this invention.

In general, the polymerizations of this invention are carried out in aninert solvent, and are, thus, solution polymerizations. By the term"inert solvent" is meant that the solvent or diluent does not enter intothe structure of the resulting polymer nor does it adversely affect theproperties of the resulting polymer nor does it have any adverse effecton the activity of the catalyst employed. Such solvents are usuallyaliphatic, aromatic, or cycloaliphatic hydrocarbons, examples of whichare pentane, hexane, toluene, benzene, cyclohexane and the like.Dichloromethane, tetrachloroethylene, monochlorobenzene and the likealso may be used as the solvent. Preferred solvents are hexane andbenzene. The solvent/monomer volume ratio may be varied over a widerange. Up to 20 or more to 1 volume ratio of solvent to monomer can beemployed. It is usually preferred or more convenient to use asolvent/monomer volume ratio of about 3/1 to about 6/1. Suspensionpolymerization may be carried out by using a solvent in which thepolymer formed in insoluble. Since many of the polymers prepared withthis novel catalyst system have relatively high molecular weights, anextender oil may be added to the system and the polymerization conductedin its presence, in which case the oil may serve also as a diluent orpolymerization solvent. It should be understood, however, that it is notintended to exclude bulk polymerizations from the scope of thisapplication.

It is usually desirable to conduct the polymerizations of this inventionemploying air-free and moisture-free techniques.

The temperatures employed in the polymerizations of this invention arenot critical and may vary from a very low temperature such as -10° C. orbelow up to high temperatures such as 100° C. or higher. However, it isusually more desirable to employ a more convenient temperature betweenabout 20° C. and about 90° C.

The practice of this invention is further illustrated by reference tothe following examples which are intended to be representative ratherthan restrictive of the scope of this invention. Unless otherwise noted,all parts and percentages are by weight. Dilute solution viscosities(DSV) of the polymers have been determined in toluene at 30° C. Glasstransition temperatures (Tg) have been determined using a DuPont ModelNo. 900 Differential Thermal Analyzer (DTA). The melting temperature(Tm) of the polymers generally have been determined with the DuPont No.900 DTA, but in a few instances a Perkin-Elmer Differential ScanningCalorimeter was used. The number average molecular weight (M_(n)) wasdetermined using a Mecrolab Model No. 501 membrane osmometer.

EXAMPLE I

A purified butadiene (BD) in benzene solution containing 100 grams (gms)of butadiene per liter of solution was charged into a series of 4-ouncebottles. The catalyst components were charged by "in situ" addition inthe following order (1) triethylaluminum (TEAL), (2) ferric octanoate(FeOct), and (3) a nitrogen containing ligand, as identified in Table I.The bottles were capped tightly, placed in a water bath maintained at50° C. and then tumbled end over end. The polymerizations wereterminated by mixing the polymer cements with one part both oftriisopropanolamine and dibutyl-paracresol per hundred parts of monomer.The polymers were dried under vacuum.

Column 1 shows the experiment number, columns 2 through 4 show theamount of catalyst used, column 5 shows the polymerization time, column6 shows the polymer yield, and columns 7 through 9 show themicrostructure makeup of the polymer.

                                      Table 1                                     __________________________________________________________________________    Exp.                                                                             Millimole/100 g. BD                                                                            Time,                                                                             Yield,                                                                            IR analysis, %                                    No.                                                                              TEAL                                                                              FeOct                                                                             N-Ligand Hours                                                                             Wt. %                                                                             cis-                                                                             trans-                                                                            1,2-                                       __________________________________________________________________________    1  1   0.1 0.1  TCNE.sup.1                                                                        19  77     ND.sup.5                                       2  12  4.0 2.0  TCNE                                                                              1   84  48 18  34                                         3  3   1.  2.   AN.sup.2                                                                          22  63  55 14  32                                         4  3   1   1    ACH.sup.3                                                                         1   100    ND                                             5  3   1   1    AIBN.sup.4                                                                        0.25                                                                              97     ND                                             __________________________________________________________________________     .sup.1 TCNE = tetracyanoethylene                                              .sup.2 AN = acrylonitrile                                                     .sup.3 ACH = acetonecyanohydrin                                               .sup.4 AIBN = azobisisobutyronitrile                                          .sup.5 ND = not determined.                                              

These polybutadiene polymers were solids which had only limitedsolubility in benzene. The polymer microstructures were estimatedutilizing an infrared film technique. The polymer prepared in ExperimentNo. 1 had a glass transition temperature, Tg., equal to -32° C.

EXAMPLE II

A premix containing 20 volume percent of isoprene in hexane was preparedand passed down a column of silica gel. A series of four-ounce bottleswas charged with 75 ml. of premix and sparged with dry nitrogen.Catalysts were then injected in the amounts indicated in Table 2, thebottles were tumbled end-over-end in a water bath at 50° C. for theindicated times and the contents were tray dried. Polymerization did notoccur in Experiments Nos. 1 to 3; the low yields reported in Table 2were mostly catalyst residues, and a trace of isoprene oligomers. It isnecessary to have present each of the three types of catalyst componentsin order to produce solid polymers.

                  Table 2                                                         ______________________________________                                        Exp.   Catalyst, mhm.sup.1                                                                           Time,   Yield,                                                                              DSV                                      No.    TEAL    FeOct   AIBN  Hours Wt. % dl/g.                                ______________________________________                                        1      3       1       0     22     1    --                                   2      3       0       1     22     2    --                                   3      0       0.5     0.5   22     1    --                                   4      3       0.5     0.5   4     33    ND                                   5      2       1       1     0.5   41    12                                                          TCNE                                                   6      3       1       0.5   0.5   76    11                                   ______________________________________                                         .sup.1 mhm = millimoles per hundred parts monomer.                       

EXAMPLE III

The procedure in this example is similar to Example I except thatdifferent iron compounds are utilized in the catalyst compositions:

                                      Table 3                                     __________________________________________________________________________    Exp.                                                                             Millimole/100 g. BD                                                                           Time,                                                                             Yield                                                                             IR Analysis, %                                     No.                                                                              TEAL                                                                              Fe    N-Lig.                                                                              Hours                                                                             Wt. %                                                                             Cis-                                                                             trans-                                                                             1,2-                                       __________________________________________________________________________    1  12  4 FeOct.sup.a                                                                       2 TCNE.sup.e                                                                         1  84  48 18   34                                         2   6  6 FeCl.sub.3.sup.b                                                                  1 TCNE.sup.f                                                                        1.7 98  High                                                                             Syndio-                                                                            1,2-PBD                                    3  12  3 Fe(CO).sub.5.sup.c                                                                3 BuSCN.sup.g                                                                       17. 71  12  2   86                                         4   3  1 Fe(Aa).sub.3.sup.d                                                                1 BuSCN.sup.h                                                                       0.16                                                                              100 ND                                                 __________________________________________________________________________     .sup.a FeOct = ferric octanoate                                               .sup.b FeCl.sub.3 = ferric chloride                                           .sup.c Fe(CO).sub.5 = iron pentacarbonyl                                      .sup.d Fe(Aa).sub.3 = iron acetylacetonate                                    .sup.e TCNE = tetracyanoethylene                                              .sup.f TCNE = tetracyanoethylene                                              .sup.g BuSCN = butyl thiocyanate                                              .sup.h BuSCN = butyl thiocyanate                                         

An X-ray diffraction pattern of Polymer No. 2 revealed that it had ahigh degree of crystallinity and that its structure was largelysyndiotactic 1,2-polybutadiene. This polymer had a Tg=-21° C. and a Tm.of about 135° C. The polymer prepared with iron pentacarbonyl containedan estimated 86 percent syndiotactic 1,2-polybutadiene based upon a filminfrared spectrum.

EXAMPLE IV

This example illustrates the use of various reducing agents with an ironcatalyst, using butadiene as the monomer polymerized. The techniquesused in this example were similar to those used in Example I.

                                      Table 4                                     __________________________________________________________________________    Millimole/100 g. BD                                                           Exp.                                                                             Reducing       Time,                                                                             Yield,                                                                            IR Analysis, %                                      No.                                                                              Agent                                                                              FeAcAc.sub.3                                                                       BuSCN                                                                              Min.                                                                              Wt. %                                                                             Cis-                                                                             Trans-                                                                            1,2-                                         __________________________________________________________________________    1  0.6.sup.A                                                                          0.05 0.1  38  59     ND                                               2  1.2.sup.B                                                                          0.2  0.4  22  91     ND                                               3  3.0.sup.B                                                                          1.0  1.0  15  100 31 3   66                                           4  12.0.sup.C                                                                         2.0  2.0  18 hr.                                                                            100 33 6   61                                           5  12.0.sup.D                                                                         2.0  2.0  13 min.                                                                           89  24 8   68                                           6  3.0.sup.E                                                                          1.0  0.5.sup.(a)                                                                        35  96     ND                                               7  2.0.sup.F                                                                          1.0.sup.(b)                                                                        0.5.sup.(a)                                                                        60  70     ND                                               8  1.0.sup.G                                                                          0.5  0.5.sup.(c)                                                                        30  100    ND                                               __________________________________________________________________________     .sup.A TEAL                                                                   .sup.B Et.sub.2 AlOEt = diethyl aluminum ethoxide                             .sup.C DEAC = diethyl aluminum chloride                                       .sup.D BuLi = butyl lithium                                                   .sup.E Et.sub.4 LiAl = tetraethyl aluminum lithium                            .sup.F NaAlEt.sub.2 H.sub.2 = sodium diethyl aluminum hydride                 .sup.G Et.sub.2 AlCN = diethyl aluminum cyanide                               .sup.(a) TCNE                                                                 .sup.(b) FeOct                                                                .sup.(c) AIBN                                                            

All of the polymers were solids. The soluble portion of Polymer No. 7had a DSV of 2.4 dl/g, but 78 percent of the polymer was insoluble intoluene. The infrared analyses were estimated on soluble portions of thepolymers, using a film technique. Polymer No. 2 had a Tg -27° C.

EXAMPLE V

A C₆ -containing hydrocarbon fraction had the following analysis by GLC(gas-liquid chromatography); 72.5 percent 2-methyl-1,3-pentadiene, 11.0percent 4-methyl-1,3-pentadiene, 9.2 percent 1-methyl cyclopentene, 1.2percent benzene and 6 percent of other C₆ -hydrocarbons which mostlywere olefins. Four hundred twenty milliliters (420 ml.) of thishydrocarbon fraction was mixed with 1520 ml. of hexane, and passed downa column containing 300 ml. of silica gel. Then 100 ml. of the solutionwas charged to each of a series of 4-ounce glass bottles and was spargedwith nitrogen. Each bottle contained approximately 12.1 grams of amixture of 2- and 4-methyl-1,3-pentadienes. Catalysts were injected andpolymerizations were conducted at 50° C. with the results as summarizedin Table 5.

                  Table 5                                                         ______________________________________                                        Exp. Catalyst, mhm.sup.1                                                                            Time,   Yield,                                                                              DSV                                       No.  TIBAL    FeOct   AIBN  Hours Wt. % dl/g.                                                                              % Gel                            ______________________________________                                        1    2        0.5     0.5   22    33    5.60 18                               2    3        1       1     22    55    5.57 12                               3    5        2       2      6    68    4.68 11                               4    6        4       2     22    68    4.03 21                               5    6        3       3      6    77    4.01 13                               6    12       6       6      4    92    2.86 15                               ______________________________________                                         .sup.1 mhm = millimoles per 100 grams of monomer.                        

The osmotic Mn (number average molecular weight) of the polymers fromExp. Nos. 1 and 4 were 303,000 and 219,000, respectively. The Tg's ofPolymer Nos. 2 and 3 were -22° and -16° C., respectively. NMR analysisof Polymer No. 3 indicated 15 percent 1,2-, 75 percent 1,4- and 10percent 3,4-structure. An unmasticated gum stock had an ultimate (atbreak) tensile strength of 200 psi and an ultimate elongation of 1000percent.

EXAMPLE VI

A preformed catalyst was prepared by injecting into a N₂ flushed andsealed four-ounce bottle, (a) 20 millimoles isoprene in hexane solution,(b) 2 millimoles of 0.25 M TEAL, (c) 1 millimole of 0.25 M FeOct, and(d) 1 millimole of 0.25 M azobisisobutyronitrile (AIBN). The totalvolume was 29 milliliters.

A purified isoprene (IP) in hexane premix containing 13.3 gms. IP perliter was prepared and 75 ml. was charged to a four-ounce bottle. Then2.9 ml. of the above preformed catalyst was injected into the premix andthe bottle was tumbled end-over-end in a water bath at 50° C. Thecontents became almost solid after 50 minutes and the polymerization wasterminated by adding one phm. of triisopropanolamine and one phm ofdibutylparacresol (DBPC).

The yield of dried polymer was 94.5 percent. It had a DSV of 10 dl/g;its gel content was reported to be 13 percent. NMR analysis indicatedits microstructure to be about 57 percent 1,4- and 43 percent3,4-polyisoprene.

EXAMPLE VII

A trans-piperylene premix was prepared by placing enough of a purifiedpiperylene fraction (analysis 95.6 percent trans-piperylene, 3.3 percentcis-piperylene and one percent cyclopentene) in benzene to have 100grams of piperylene per liter of solution. Seven different alkylaluminumcompounds were used and three different iron salts were employed. Thecatalyst concentration in all instances was R₁ R₂ R₃ Al:FeX₃ :AIBN=3:1:1millimole/100 g. monomer. Polymerization temperature was 50° C. and thetime was one hour except for Experiment No. 11 which was 3.5 hours.

                  Table 6                                                         ______________________________________                                                            Yield, Wt. %                                              Exp.                1.0 Hr.            Tg,                                    No.  R.sub.1 R.sub.2 R.sub.3 Al                                                                   FeX.sub.3 = Fe Octoate                                                                      DSV  °C.                             ______________________________________                                        1    TEAL.sup.a     94            4.6  -1                                     2    TNPAL.sup.b    94            4.8  ND                                     3    TNHAL.sup.c    94            4.4  -12                                    4    TIBAL.sup.d    93            5.2  -2                                     5    TIHAL.sup.e    91            4.7  -3                                     6    DEA-H.sup.f    87            4.8  ND                                     7    DIBA-H         93            5.8  -6                                      .sup.a triethylaluminum                                                       .sup.b tri-n-propylaluminum                                                   .sup.c tri-n-hexylaluminum                                                    .sup.d triisobutylaluminum                                                    .sup.e triisohexylaluminum                                                    .sup.f diethylaluminum hydride                                           

    8                   FeX.sub.3 = Fe (AcAc).sub.3                               8    TEAL           95            2.3  -20                                    9    TIBAL          97            3.4  ND                                      10  DIBA-H         97            3.2   0                                                         FeX.sub.3 = Fe stearate                                    11  TIBAL (in 31/2 hours)                                                                         66%          5.0  -8                                     ______________________________________                                    

EXAMPLE VIII

A purified premix containing 90 grams per liter of dimethylbutadiene(DMB) in toluene was prepared, and 80 ml. was charged to a series offour-ounce bottles. Catalysts were charged and results obtained assummarized in Table 7. All polymerizations were conducted at 50° C.except Experiment No. 5 which was at 25° C.

                                      Table 7                                     __________________________________________________________________________       Catalyst                                                                   Exp.                                                                             Millimole/100 g. DMB                                                                      Time,                                                                             Yield,                                                                            NMR Anal., %                                           No.                                                                              TEAL                                                                              FeOct                                                                             TCNE                                                                              Mins.                                                                             Wt. %                                                                             1,4-      1,2-                                         __________________________________________________________________________    1  1.  0.5 0.25                                                                              30  58       ND                                                2  2.  1.0 0.50                                                                              30  62  81        19                                                      AIBN                                                               3  2.  1.0 1.0 15  100 83        17                                           4  3.  2.0 1.0 15  96       ND                                                5  3.  2.0 1.0 45  96  78        22                                                  FeCl.sub.3                                                                        TCNE                                                               6  6.  6.0 1.0 15  100 93         7                                           __________________________________________________________________________

An X-ray diffraction pattern of the polymer produced in Experiment No. 4showed that it was highly crystalline and its structure was primarilythat of cis-1,4-poly(2,3-dimethyl-1,3-butadiene).

EXAMPLE IX

A purified premix containing 10 grams of dimethylbutadiene (DMB) per 100ml. of solution was prepared by adding 280 ml. of DMB to 1720 ml. ofPhillips' ASTM grade normal heptane, passing it down a column of silicagel and finally sparging it with nitrogen. Polymerizationtemperature=50° C.

                                      Table 8                                     __________________________________________________________________________    Exp.                                                                             Millimole/100 g. DMB                                                                          Time,                                                                             Yield                                                                             DSV                                                                              %   Tg.                                         No.                                                                              TIBAL FeOct                                                                              AIBN mins.                                                                             Wt. %                                                                             dl/g.                                                                            Insol.                                                                            °C.                                  __________________________________________________________________________    1  3.0   1.0  6    50  9.4 53 -13                                             2  3.0   0.5  0.5  3   95  3.1                                                                              97  -33                                            TEAL                                                                       3  3.0   1.0  1.0  4   71  6.5                                                                              70  -27                                         __________________________________________________________________________

X-ray diffraction patterns revealed that all three polymers weremoderately to highly crystalline, and their crystalline structure wasprimarily that of cis-1,4-poly(2,3-dimethylbutadiene). The meltingtemperature, Tm, of these polymers was about 149° C.

EXAMPLE X

A premix containing 17.5 volume percent of a distillate fraction whichanalyzed 86 percent isoprene was prepared in benzene. After drying thepremix by passing it down a column of silica gel, and then sparging withdry nitrogen, the resulting premix contained 100 gms. of isoprene perliter of solution. A series of four-ounce bottles containing aliquots ofthis premix were charged with a variety of catalyst concentrations andratios and placed in 50° C. bath, and some of the results are summarizedin Table 9.

                                      Table 9                                     __________________________________________________________________________    Exp.                                                                             Catalyst, mhm   Time,                                                                             Yield,                                                                             DSV                                                                              %  Tg.                                         No.                                                                              TIBAL                                                                              Fe(AcA).sub.3                                                                        AIBN                                                                              Hours                                                                             Wt. %                                                                              dl/g.                                                                            Gel                                                                              °C.                                  __________________________________________________________________________    1  3    0.1    0.1 18  100  19 60 -25                                         2  3    0.1    1.0 0.8 61   12 13 -24                                         3  3    0.3    0.3 1.5 76   13 14 ND                                          4  3    1.0    1.0 0.25                                                                              81   10 11 -31                                         5  3    0.1    10.0                                                                              18  18   4.6                                                                              28 -34                                         6  40   0.1    2.0 2   34   14 52 -24                                         __________________________________________________________________________

Polymer Nos. 2, 3 and 6 were analyzed by infrared using a solutionmethod. The respective analyses were 40, 38 and 37 percent of 1,4-; 56,59 and 59 percent of 3,4-; and 3 percent of 1,2-polyisoprene in eachpolymer.

EXAMPLE XI

A premix solution containing 15 volume percent of isoprene in hexane, or10 gms. of isoprene per 100 ml. of purified solution, was prepared. Aseries of four-ounce bottles containing aliquots of this premix werecharged with equal amounts of catalyst, namely TEAL: FeOct: AIBN=2:1:1millimole per 100 gms. of isoprene, and different bottles werepolymerized at each of three different temperatures. The results aresummarized in Table 10.

                                      Table 10                                    __________________________________________________________________________    Exp.                                                                             Temp.                                                                             Tims,                                                                             Yield DSV     %  NMR, %                                            No.                                                                              °C.                                                                        Hours                                                                             Wt. % dl/g.   Gel                                                                              1,4-  3,4-                                        __________________________________________________________________________    1   0  22  14     3.4    20 53    47                                          2  25  1   10     3.9    25 51    49                                          3  25  7   60    11.5    15 53    47                                          4  50  1   64    14.5     7    ND                                             5  50  2   93        ND     51    49                                          __________________________________________________________________________

Polymerization occurred much more readily at the higher polymerizationtemperatures. All polymers were comprised of approximately 50 percent1,4- and 50 percent 3,4-polyisoprene. The osmotic number averagemolecular weight, Mn, of Polymer No. 4 was 966,000.

EXAMPLE XII

Premix solutions containing 15 volume percent of isoprene (IP) in hexanewere prepared and 750 ml. of solution (75 gms. of isoprene) were chargedto each of a series of quart bottles. To some of these bottles, arelatively naphthenic type extender oil having a specific gravity of0.90, and which had been dried over molecular sieves, was added bysyringe. Catalysts were injected and then the bottles were placed in awater bath controlled at 50° C. and the isoprene was polymerized whilethe bottles were rotated end-over-end. Typical conditions and resultsare presented in Table 11. In Experiments Nos. 2 and 4, 19 and 58 ml. ofextender oil were added to the premix prior to addition of thecatalysts. Experiments 1 and 3 were conducted without the addition ofextender oil. Polymerization proceeded satisfactorily in the presence ofthe extender oil.

                                      Table 11                                    __________________________________________________________________________    Exp.                                                                             Catalyst, mhm                                                                             Time,                                                                             Yield, wt %                                                                         Oil                                                                              ML-4 DSV                                                                              %                                         No.                                                                              TEAL                                                                              FeOct                                                                             Ligand                                                                            Hours                                                                             basis IP                                                                            phr                                                                              at 212° F.                                                                  dl/g                                                                             Gel                                       __________________________________________________________________________               AIBN                                                               1  2   1   1   1.0 73     0 44   11.1                                                                             23                                        2  2   1   1   1.5 77    30 29    7.3                                                                             23                                                   TCNE                                                               3  1   0.5 0.25                                                                              2   84     0 51   19.7                                                                             18                                        4  2   0.5 0.25                                                                              3   100   67 22    5.6                                                                             10                                        __________________________________________________________________________

EXAMPLE XIII

A butadiene in benzene premix was prepared by the procedure described inExample I. The relative polymerization activity of a number ofdicyano-ligands containing from 1 to 4 carbon atoms attached in a chainbetween the two cyano groups was compared. The results are summarized inTable 12.

                                      Table 12                                    __________________________________________________________________________    Exp.                                                                             Millimole/100 g. BD                                                                        Time,                                                                             Yield       %  IR Analysis, %                             No.                                                                              TEAL                                                                              FeOct                                                                             Nitrile                                                                            Hours                                                                             Wt. %                                                                             dl/g.   Gel      trans-                                                                            1,2-                             __________________________________________________________________________               Malono-                                                            1  0.5 0.25                                                                              0.25 20  65  1.09    11 81    1   18                                      FeDec                                                                             Fumaro-                                                            2  1.5 0.5 0.5  18  86  1.37    19 54    8   38                               3  3   1.0 0.5  18  93  1.22    13    ND                                      4  3   1.0 2.0  18  81  1.72    30 50    7   43                                      FeOct                                                                             Succino-                                                           5  3   1.0 1.0  19  25       ND       ND                                                 Glutaro-                                                           6  1   0.5 0.5  19  4   (rubbery)     ND                                                 Adipo-                                                             7  1   0.5 0.5  19  0.4                                                       8  1   0.5 0    19  1.7                                                       __________________________________________________________________________

Malononitrile, succinonitrile and fumaronitrile were active ligands;glutaronitrile produced only a four percent yield of polymer, which wassolid and rubbery, during 19 hours. Polymerization did not occur in thepresence of adiponitrile; the trace of yield reported in Table 12 wasoily, possibly an oligomer or thermal dimer, similar to that in thecontrol (Experiment No. 8) run in the absence of any nitrile.

EXAMPLE XIV

A premix was prepared by adding 310 ml. of a cispiperylene fraction,which analyzed 94.6 percent cis- and 5.3 percent trans-1,3-pentadiene to1690 ml. of hexane. The premix was passed down a column of silica gel,aliquots of 100 ml. were measured into a series of four-ounce bottlesand the contents were sparged with nitrogen. Each bottle containedapproximately 10 gm. of piperylene. The amount of catalyst charged andthe duration of polymerization, at 50° C., are shown in columns 2through 5 in Table 13.

                                      Table 13                                    __________________________________________________________________________    Exp.                                                                             Catalyst, mhm.sup.1                                                                        Time, Yield                                                                             DSV                                                                              %   Tg                                           No.                                                                              TIBAL                                                                              FeOct                                                                             AIBN                                                                              Hours Wt. %                                                                             dl/g                                                                             Gel,                                                                              °C.                                   __________________________________________________________________________    1  1.sup.2                                                                            0.3 0.3 20    94  10.7                                                                             10  ND                                           2  2    0.5 0.5 3     74  8.0                                                                              10  ND                                           3  3    1.0 1.0 1     76  7.7                                                                              13  -55                                          4  3    1.0 1.0 1.3   92  ND     ND                                           5  6    2.0 1.0 1     68  3.9                                                                              13  -56                                          __________________________________________________________________________     .sup.1 Millimole per 100 grams of monomer (piperylene).                       .sup.2 TEAL, rather than TIBAL, was charged in Exp. No. 1.               

The polymers were readily soluble in aromatic hydrocarbons. Infraredanalysis by a solution method of Polymer No. 1 indicated that itsmicrostructure was 93 percent cis-, 4 percent trans- and 3 percent3,4-polypentadiene. The microstructure of Polymer No. 3 as determined byinfrared was 90 percent cis-, 6 percent trans- and 3 percent3,4-polypentadiene, while by NMR it was 87 percent 1,4-, 7 percent 1,2-and 5 percent 3,4-.

X-ray diffraction patterns of Polymer Nos. 3 and 4 positively identified(identity period=8.1A) them as crystalline isotacticcis-1,4-polypentadienes. Polymer No. 3 also had a melting temperature,Tm, equal to 50° C.

EXAMPLE XV

A premix was prepared by adding 167 ml. of Phillips' rubber gradebutadiene to 1683 ml. of dry benzene, and then adding 150 ml. ofisoprene. The premix was passed down a column of silica gel, charged toa series of 4-ounce bottles and sparged with nitrogen. It contained anestimated 5 gm. of butadiene and 5 gm. of isoprene per 100 ml. ofsolution.

Dialkylaluminum halides were used rather than trialkylaluminums in thisseries of experiments. All polymerizations were conducted at 50° C. for17 hours.

                  Table 14A                                                       ______________________________________                                        Exp.   Millimole/100 g. Monomers                                                                            Yield   DSV                                     No.    DEAB       FeOct     TCNE    Wt. % dl/g.                               ______________________________________                                        1      12         1         0.5     100   9.3                                                             AIBN                                              2      12         1         2       100   4.3                                        DEAI.sup.2                                                             3      12         1         2       100   9.6                                 ______________________________________                                         .sup.1 DEAB - diethylaluminum bromide                                         .sup.2 DEAI - diethylaluminum iodide.                                    

                  Table 14B                                                       ______________________________________                                        Infrared Analysis, %                                                          Exp.  Polybutadiene      Polyisoprene Tg                                      No.   cis-1,4- trans-1,4-                                                                              1,2-  cis-1,4-                                                                             3,4-  °C.                        ______________________________________                                        1     4        0.4       37    41     18    -26                               2     3        0.6       38    42     17    -27                               3     3        0.3       35    41     18    -26                               ______________________________________                                    

EXAMPLE XVI

A premix solution containing approximately 5 gm. of isoprene and 5 gm.of total piperylenes (the piperylene fraction analyzed 88% trans-1,3, 8%cis-1,3-pentadiene, 1,3% isoprene, 1% cyclopentene, 0.2% 1-pentyne and1.5% unknowns) in 100 ml. in benzene was prepared, purified by passingdown a column of silica gel and sparging with nitrogen, and thenpolymerized in 4-ounce bottles at 50° C. The polymerization conditionsand polymer yields are summarized in Table 15A, and the polymer analysesare summarized in Table 15B.

                  Table 15A                                                       ______________________________________                                              Catalyst Charge,                                                        Exp.  Millimole/100 g monomers -                                                        Yield                                                               No.   TEAL      FeOct     TCNE    Hours  Wt. %                                ______________________________________                                        1     2         1         0.5     1.5    73                                   2     3         1         0.5     17.5   99                                                             AIBN                                                3     2         1         1       0.5    62                                   4     2         1         1       1.5    93                                   5     3         1         1       0.5    76                                   6     6         2         2       0.5    96                                   ______________________________________                                    

                  Table 15B                                                       ______________________________________                                                    Infrared Analysis, %                                              Exp. DSV    %      Tg   Polyisoprene Polypiperylene                           No.  dl/g   Gel    °C.                                                                         cis-1,4-                                                                             3,4-      trans- 3,4-                          ______________________________________                                        1    4.9    19     -34  32     32        31     5                             2    2.9    17      ND              ND                                        3    6.8    18     -19  29     37        29     5                             4    6.6    17     -17  27     30        38     5                             5    ND     ND      ND              ND                                        6    4.3    12      ND              ND                                        ______________________________________                                    

EXAMPLE XVII

A butadiene (BD) in heptane solution was prepared by the addition of 333ml. of 1,3-butadiene to 1667 ml. of heptane; and 280 ml. of2,3-dimethyl-1,3-butadiene (DMB) was added to 1620 ml. of heptane. Eachof these solutions were dried by passing down columns of silica gel.Premixes of different compositions were prepared by blending aliquots ofthese solutions in a series of 4-ounce bottles. The catalyst charge wasTIBAL:FeOct:AIBN=3:1:1 millimole per 100 gm. of monomers. Polymerizationtemperature was 50° C. The resulting polymers were relatively hard andnonrubbery.

                  Table 16                                                        ______________________________________                                             Monomer Charge,                                                          Exp. Wt. Ratio     Time,   Yield DSV   %    Tg,                               No.  DMB      BD       Mins. Wt. % dl/g  Gel  °C.                      ______________________________________                                        1    70       30       75    44    7.3   52   -21                             2    50       50       25    57    5.2   82   -26                             3    30       70       10    51    2.2   93   ND                              4    30       70       15    67    ND    ND   -43                             ______________________________________                                    

EXAMPLE XVIII

One Hundred and Forty (140) milliliters of 2,3-dimethyl-1,3-butadiene(DMB) were mixed with 860 ml. of Phillips' pure grade n-heptane. Asecond solution containing 315 ml. of a 95 percent trans- plus 3 percentof cis-1, 3-pentadiene (PD) in 1685 ml. of n-heptane was prepared. Eachsolution was passed down a separate silica gel column. Blends of thesetwo solutions were prepared by charging separate aliquots to a series of4-ounce bottles. The solutions were then sparged with nitrogen; thepurified premixes were assumed to contain a total of 10 gm. ofdimethylbutadiene (DMB) and piperylene (PD) per 4-ounce bottle. Thepolymerizations were catalyzed by "in situ" addition of 3:1:1 mhm ofTIBAL:FeOct:AIBN and polymerizing at 50° C.

                                      Table 17                                    __________________________________________________________________________    Exp.                                                                             Charge, Wt. %                                                                         Time,                                                                              Yield                                                                             DSV %  Tg X-ray;                                          No.                                                                              DMB/t-PD                                                                              Hours,                                                                             Wt. %                                                                             dl/g                                                                              Gel                                                                              °C.                                                                       Crystallinity                                   __________________________________________________________________________    1  100:0   0.10 50  9.4 53 -13                                                                              Yes; cis-1,4-                                                                    PDMB                                         2  80:20   0.75 60  6.8 23 -13                                                                              Amorphous                                       3  50:50   1.50 57  5.1  9 ND    ND                                           4  50:50   4.0  91  5.2 12 -9 Amorphous                                       5  20:80   2.0  70  4.7  6 -7 Slightly; si-                                                                 milar to No. 6                                  6  0:100   0.5  93  4.5 27 -4 Slightly; syn-                                                                dio-trans-1,2-                                                                   PPD                                          __________________________________________________________________________

Since the homopolymers are crystalline, the amorphous diffractionpatterns indicate the relatively random structure of the copolymers.

EXAMPLE XIX

A series of polymers were prepared in a manner similar to that describedin Example XVIII except that only one-half as much catalyst(1.5:0.5:0.5=TIBAL:FeOct:AIBN) was charged to catalyze the copolymers inthe present experiment. This series of polymers was analyzed by NMR, butnot by X-ray.

                                      Table 18                                    __________________________________________________________________________                                  NMR, %                                          Exp.                                                                             Charge, Wt. %                                                                         Time,                                                                             Yield                                                                             DSV %  Tg,     PDMB                                        No.                                                                              DMB/t-PD                                                                              Hours                                                                             Wt. %                                                                             dl/g                                                                              Gel                                                                              °C.                                                                        PPD 1/4  1,2                                    __________________________________________________________________________    1  100:0    0.05                                                                             63  8.4 52 -20  0  72   28                                     2  80:20   18. 85  8.0 53 -27 19  57   24                                     3  20:80   18. 86  8.0 12 -13 74  21    5                                     __________________________________________________________________________

The gum rubber produced in Experiment No. 2 was pressed into 1/8-inchthick dumbbells and had an ultimate elongation=600 percent. Similarproperties for Polymer No. 3 were 490 psi and 700 percent.

EXAMPLE XX

A by-product C₅ -hydrocarbon stream was fractionated. It analyzed bygas-liquid chromatography 53.3% cis-1,3-pentadiene, 8.0%trans-1,3-pentadiene, 34% cyclopentene, 3.1% 2-methyl-2-butene and0.075% 3-penten-1-yne. A premix containing 10 grams of the pentadienesper 100 ml. was prepared in hexane, passed down a silica gel column, andeither 100 or 50 ml. was measured into 4-ounce bottles. To the bottlecontaining only 50 ml. of premix, 7 cc. of 99 percent2,3-dimethyl-1,3-butadiene (DMB) from Chemical Samples Company plus 40cc. of deaerated hexane were injected by syringe, resulting inapproximately 5 g. of piperylenes plus 5 g. of DMB in the final premix.The DMB had not been freshly dried and extra TIBAL was added to initiatepolymerization. Catalyst added to Experiment No. 1 wasTIBAL:FeOct:AIBN=4:2:2 millimoles per 100 g. of monomer while inExperiment No. 2 it was 10:1:1 mhm. Two results are summarized in Table19.

                  Table 19                                                        ______________________________________                                        Exp. Charge, Wt. %                                                                              Time    Yield DSV   %    Tg.                                No.  DMB:PD       Hours   Wt. % dl/g. Gel  °C.                         ______________________________________                                        1    0:100         3       80   4.1   12   -60                                2    50:50        23      100   2.3   12   -27                                ______________________________________                                    

An X-ray diffraction pattern of Polymer No. 1 showed that it was highlycrystalline and it was identified as isotactic cis-1,4-polypiperylene.The X-ray diffraction pattern of Polymer No. 2 was amorphous, indicatinga relatively random copolymer. NMR analysis of Polymer No. 1 revealedthat its microstructure was 87% 1,4- and 13% 1,2-polypiperylene.

EXAMPLE XXI

Solutions of two piperylene monomers were prepared in hexane, so thateach solution contained 10 gm. of piperylenes per 100 ml. of solution.The trans-piperylene monomer analyzed 95.6% trans-1,3-pentadiene, 3.3%cis-1,3-pentadiene and 1% cyclopentane; the cis-piperylene monomeranalyzed 94.6% cis-1,3-pentadiene and 5.3% trans-1,3-pentadiene. Thehexane solutions of these monomers were passed down separate columns ofsilica gel, and then aliquots of each were added to a series of 4-ouncebottles to prepare premixes containing the cis- and trans-monomers indifferent ratios, e.g., 25/75, 50/50 and 75/25. The polymerizations werecatalyzed by charging the catalyst TIBAL:FeOct:AIBN=3:1:1 millimole/100gm. of monomers and tumbling end-over-end in a 50° C. water bath. Theresults are summarized in Table 20.

                                      Table 20                                    __________________________________________________________________________       Charge                                                                     Exp.                                                                             cis:trans                                                                           Time,                                                                             Yield,                                                                            DSV %  Tg, NMR, %                                            No.                                                                              1,3-PD                                                                              Hours                                                                             Wt.%                                                                              dl/g                                                                              Gel                                                                              °C.                                                                        1,4-                                                                              1,2-                                                                              3,4-                                      __________________________________________________________________________    1  25:75  2  79  3.7 14 -5  25  73  2                                         2  50:50  2  58   3.3.sup.a                                                                        13 -7  51  48  1                                         3  50:50 18  99  4.3  9 .sup.b  ND                                            4  75:25 18  98  5.8  5 -59 78  22  0                                         __________________________________________________________________________     .sup.a Mn (by osmotic membrane method) = 290,000.                             .sup.b Polymer No. 3 had a Tg at both -60° and -2° C.      

Polymers No. 1 and 2 were plastic-like, similar to syndiotactictrans-1,2-polypiperylene. Polymers No. 3 and 4 were rubbery, but weresomewhat tougher than isotactic cis-1,4-poolypiperylene. The two isomerscopolymerize although there apparently is some block copolymerizationdue to the fact that the trans-isomer tends to polymerize more rapidlythan does the cis-isomer.

EXAMPLE XXII

Three separate solutions of monomers in heptane were prepared. Two ofthese, 2,3-dimethyl-1,3-butadiene (DMB) and the 95% trans-1,3-pentadiene(PD), were part of the same solutions used in Example XVIII; the thirdwas 1,3-butadiene (BD) in heptane as prepared in Example XVII. Each ofthe solutions contained 10 g. of the respective monomer per 100 ml. ofsolution. Aliquots of these solutions were added to 4-ounce bottles andterpolymerizations were conducted after injection of the catalyst, whichwas TIBAL:FeOct:AIBN=3:1:1 millimole per 100 gm. of total monomers.Polymerization temperature was 50° C. The polymerizations were stoppedwhen viscous polymer cements formed in order to mix adequately thestabilizer into the polymers.

                  Table 21                                                        ______________________________________                                        Exp. Monomer Charge,Wt.%                                                                          Time,   Yield DSV  %    Tg                                No.  DMB:    BD:    t-PD  Hours Wt. % dl/g Gel  °C.                    ______________________________________                                        1    50      25     25    1.0   30     ND  ND   ND                            2    25      50     25    0.5   59    7.0  58   -27                           3    23      26     51    1.0   61    5.9  11   -19                           ______________________________________                                    

These polymers were elastomeric and exhibited only one glass transitiontemperature, Tg, indicating formation of co- or terpolymers.

EXAMPLE XXIII

A premix containing approximately 100 gm. of both trans-piperylene andbutadiene was prepared by adding 158 ml. of a piperylene fraction (95.6%trans-, 3.1% cis-piperylene and 1% cyclopentene) and 167 ml. of liquidbutadiene (Phillip's rubber grade) to 1675 ml. of hexane, and purifyingit by passing it down a column of silica gel, charging 100 ml. to aseries of 4-ounce bottles, and then sparging with nitrogen. In addition,a premix containing 100 gm. of trans-piperylene per liter of solutionand another containing 100 gm. of butadiene per liter were prepared.Aliquots of these last two premixes were measured into 4-ounce bottlesin order to provide premixes containing weight ratios of 25:75 and 75:25parts of butadiene to trans-piperylene (t-PD).

The catalyst charged to the first three experiments listed in Table 22was TIBAL:FeOct:AIBN=2:0.5:0.5 millimoles per 100 gm. of monomer. Thecatalyst charged to the rest of the experiments was increased to 3:1:1mhm. The polymerizations were stopped after various time intervals inorder to obtain different degrees of conversion. Some results aresummarized in Table 22.

                                      Table 22                                    __________________________________________________________________________    Exp.                                                                             Charge, Wt.%                                                                          Time,                                                                             Yield                                                                             DSV %  IR anal., est.                                      No.                                                                              BD/t-PD mins.                                                                             Wt.%                                                                              dl/g                                                                              Gel                                                                              PBD trans-PPD                                       __________________________________________________________________________    1  50:50   20  42  7.9 8  70  30                                              2  50:50   30  68  9.5 6  64  36                                              3  50:50   45  80  8.3 8  57  43                                              4  75:25   10  76  5.9 47     ND                                              5  50:50   10  44  5.7 5      ND                                              6  50:50   15  73  6.8 5      ND                                              7  50:50   30  91  6.6 8      ND                                              8  25:75   30  70  5.7 8      ND                                              __________________________________________________________________________

Butadiene polymerized more rapidly than piperylene did. This isindicated by the higher polymer yields obtained within a given time whenusing higher BD:t-PD charge ratios, and also by the estimated infraredanalyses of the copolymers. The presence of trans-piperylene resulted inthe production of polymers which were much more soluble thanpolybutadiene homopolymers prepared with the same catalyst system. Thecopolymers were relatively tough rubbers. The ultimate or break tensileas determined on an Instron for the unmasticated gum stock on a mixtureof Polymers No. 6 and 7 was 700 psi and its elongation at break was 750percent. Polymer No. 7 had an osmotic number average molecular weightequal to 428,000.

EXAMPLE XXIV

Two experiments were performed to show that diethylaluminum cyanide (Et₂AlCN) can serve both as the organometallic agent and as a source of allof the nitrogen ligands required to create an active polymerizationcatalyst.

Two premixes, one containing 100 gm. of butadiene (BD) per liter ofbenzene solution, and the second containing 100 gm. of isoprene (IP) perliter of hexane solution, were prepared and purified in the mannerdescribed in Examples 1 and 11, respectively. Aliquots of thesesolutions were polymerized at 50° C. at the conditions and with theresults reported in Table 23.

                                      Table 23                                    __________________________________________________________________________    Exp.                                                                             Mono-                                                                             Catalyst, mhm                                                                             Time,                                                                             Yield                                                                             DSV %   Tg,                                        No.                                                                              mer FeX.sub.3                                                                           Et.sub.2 AlCN                                                                       mins.                                                                             Wt.%                                                                              dl/g                                                                              Gel °C.                                 __________________________________________________________________________    1  BD  0.5 AcAc.sup.1                                                                      12    45  48  ND  100 -19                                        2  IP  0.5 Oct.sup.2                                                                        2    60  34  10  5   -32                                        __________________________________________________________________________     .sup.1 AcAc = ferric acetylacetonate,                                         .sup.2 Oct = ferric octanoate.                                           

The polybutadiene produced with the 2-catalyst component system wasquite insoluble. Infrared analysis of a film cast from the CS₂ -solubleportion of the polymer indicated 11.5% cis-1,4-, 1.5% trans-1,4- and 87%(syndiotactic) 1,2-polybutadiene. The polyisoprene polymer was readilysoluble in aromatic hydrocarbons, carbon disulfide and carbontetrachloride. Infrared solution analysis reported its microstructure tobe 60% 1,4-, 35% 3,4- and 5% 1,2; analysis by NMR indicated 40% 1,4-,49% 3,4- and 11% 1,2-polyisoprene.

EXAMPLE XXV

A butadiene in dichloromethane premix was prepared by adding 333 ml. ofliquid butadiene to 1667 ml. of Eastman's dichloromethane, and thenpurifying the solution as described in Example I. The premix containedapproximately 10 gm. of butadiene per 100 ml. Catalysts were injectedand the solutions were polymerized at 50° C. for 2 hours. Results aresummarized in Table 24.

                  Table 24                                                        ______________________________________                                        Exp. Catalyst,mhm        Yield   DSV   %                                      No.  TIBAL    Fe(AcAc).sub.3                                                                           AIBN  Wt.%  dl/g. Gel                                ______________________________________                                        1    3        1.0        1     35    1.1   95                                 2    6        1.0        1     77    4.9   90                                 3    6        0.25       1     100   ND                                       4    20       0.1        20    81    0.8   94                                 ______________________________________                                    

Polymer No. 4 had a Tg=-24° C. All of the polymers were relativelyinsoluble. A sample of dried Polymer No. 4 was dispersed indichloromethane and the microstructure, estimated from the infraredspectra obtained on a film cast from the dispersion, was 12% cis-1,4, 1%trans-1,4- and 87% 1,2-polybutadiene.

EXAMPLE XXVI

A butadiene in hexane premix was prepared by the procedure described inExample I. The source of the nitrogen ligand employed in this series ofexperiments was diethylaluminum cyanide. Polymerizations were conductedat 50° C. for 18 hours. Catalyst concentrations and polymerizationresults are summarized in Table 25.

                                      Table 25                                    __________________________________________________________________________    Exp.                                                                             mhm            Yield                                                                             Tg, IR Anal., %                                         No.                                                                              FeOct                                                                              TEAL EACN.sup.1                                                                         Wt. %                                                                             ° C.                                                                       cis-                                                                             trans-                                                                            1,2-                                         __________________________________________________________________________    1  0.5  1    0.5  96  ND.sup.2                                                                          15 1   84                                           2  0.5  1    2.0  93  -13    ND                                                  TEAL FeCl.sub.3                                                            3  6    2    2.0  100 -25    ND                                               __________________________________________________________________________     .sup.1 EACN = diethylaluminum cyanide.                                   

Polybutadienes prepared using diethylaluminum cyanide to provide thenitrogen ligand are comprised of a relatively high percentage ofsyndiotactic 1,2-polybutadiene.

EXAMPLE XXVII

This example illustrates that monomers can be satisfactorily polymerizedin the presence of impurities such as acetylene and cyclopentadiene byemploying the catalyst system of the instant invention. The monomerutilized was trans-1,4 piperylene. The techniques used in this examplewere similar to those used in Example I.

                                      Table 26                                    __________________________________________________________________________    Exp.                                                                             Millimole/100g . monomer                                                                    Impurity                                                                            Pzn. time                                                                           Yield                                            No.                                                                              TIBAL                                                                              FeOct                                                                              AlBN                                                                              ppm*  Hrs.  Wt. %                                                                             DSV Gel                                      __________________________________________________________________________    1  3.0  1.0  1.0  --   0.5   96  4.8 13                                       2  "    "    "   1-hexyne                                                                            1.0   98  5.4 21                                                        2500                                                         3  "    "    "   CPD 50                                                                              0.5   90  5.0 20                                       4  "    "    "   CPD 500                                                                             0.5   66  5.2 32                                       __________________________________________________________________________     *parts per million.                                                      

EXAMPLE XXVIII

A premix containing 10 grams of cis-1,3-pentadiene per 100 ml. ofsolution was prepared by adding 475 ml. of a hydrocarbon fraction whichanalyzed 98.6 percent cis-piperylene to 2525 ml. of hexane, andpurifying it by passing it down a silica gel column and then sparging itwith nitrogen. Eight hundred milliliters of the premix was charged to aquart bottle. Polymerization was initiated by adding 2.4 millimoles oftriisobutylaluminum (TIBAL), 0.8 millimole of iron octoate and 0.8millimole of azobisisobutyronitrile, and tumbling ene-over-end in awater bath at 50° C. The polymerization was terminated after four hoursand the yield of dry polymer was 68.4 grams (85.5%). The Mooneyviscosity of the polymer (ML-4 at 212° F.) was 74 and its DSV was 7.4.It exhibited a sharp glass transition temperature at -60° C. An NMRanalysis reported that its microstructure was comprised of 99 percentcis-1,4- and one percent 1,2-polypiperylene.

By the term "isotactic" is meant a type of polymer structure in whichgroups of atoms which are not part of the backbone structure are locatedeither all above or all below the atoms in the backbone chain, when thelatter are arranged so as to be all in one plane.

By the term "atactic" is meant a type of polymer molecule in whichsubstituent groups or atoms are arranged randomly above and below thebackbone chain or atoms, when the latter are arranged so as all to be inthe same plane.

By the term "syndiotactic" is meant a type of polymer molecule in whichgroups or atoms that are not part of the backbone structure are locatedin some symmetrical and recurring fashion above and below the atoms inthe backbone chain, when the latter are arranged so as to be in a singleplane.

While certain representative embodiments and details have been shown forthe purpose of illustrating the invention, it will be apparent to thoseskilled in this art that various changes and modifications may be madetherein without departing from the spirit or scope of the invention.

What is claimed is:
 1. A catalyst composition suitable for thepolymerization of conjugated diolefins to stero regular solid elastomersconsisting essentially of (1) an iron containing compound selected fromthe group consisting of iron salts of carboxylic acids, organic complexcompounds of iron, iron salts of inorganic acids and iron carbonyls, (2)an organometallic reducing agent selected from the group consisting oforganoaluminum compounds, organolithium compounds and organosodiumcompounds and (3) a nitrogen containing ligand characterized in thatsaid ligand has at least two functional groups or atoms wherein thefirst functional group is a cyano group (--C.tbd.N) and the secondfunctional group is selected from the group consisting of (a) anothercyano group, (b) azo group, (c) imine group, (d) vinylene group, (e)mercapto group, and (f) thio group and there must not be more than twoadditional carbon atoms separating the first functional group and thesecond functional group, in which the mole ratio of the organometalliccompound to the iron compound ranges from about 1/1 to about 400/1 andthe mole ratio of the nitrogen ligand to the iron compound ranges fromabout 0.1/1 to about 100/1.
 2. A composition according to claim 1 inwhich the iron containing compound is selected from the group consistingof ferric hexanoate, ferric octanoate, ferric decanoate, ferricstearate, ferric naphthenate, ferrous acetylacetonate, ferricacetylacetonate, ferric-1-ethoxy-1,3-butanedionate, ferrous dimethylglyoxime, ferric chloride, ferrous chloride, ferric bromide, ferricfluoride, ferric phosphate, ferrous sulfate, iron tetracarbonyl, ironpentacarbonyl and iron nonacarbonyl and in which the organometalliccompound is defined by the formula ##STR6## in which R₁ is selected fromthe group consisting of alkyl (including cycloalkyl), aryl, alkaryl,arylalkyl, alkoxy, hydrogen, cyano and halogen, R₂ and R₃ being selectedfrom the group of alkyl (including cycloalkyl), aryl, alkaryl andarylalkyl, and in which the nitrogen containing ligand is selected fromthe group consisting of cyanogen, malonitrile, succinonitrile, methylsuccinonitrile, 1,2-dicyanobenzene, 1,2-dicyanocyclobutane,tetracyanoethane, tetracyanoethylene, hexacyanoisobutylene,2,5-diamino-3,4-dicyanothiophene, 3,4-dicyanopyrrole,2,3-dicyano-2-butene, diethylaluminum cyanide, azobisisobutyronitrile,2,2'-azobis-2,4-dimethylvaleronitrile, 2-t-butylazo-2-cyanopropane,2-t-butylazo-2-cyanobutane, 2-t-butylazo-2-cyano-4-methylpentane,2-t-butylazo-2-cyano-4-methoxy-4-methylpentane,1-t-butylazo-1-cyanocyclohexane, ethylenebis-(4-butylazo-4-cyanovalerate), 2-(t-butylazo)isobutyronitrile,iminodicyanodiamide, imino-succinonitrile, diiminosuccinonitrile,fumaronitrile, maleonitrile, 1,4-dicyano-2-butene, acrylonitrile,methacrylonitrile, 2-chloroacrylonitrile, diaminomaleonitrile,1-cyano-1-propene, 1-cyano-1,3-butadiene, 1,2-dicyano-1-butene,2-mercapto-isobutyronitrile, 2-mercapto-propionitrile, butylthiocyanate, hexyl thiocyanate, benzyl thiocyanate, phenyl thiocyanate,potassium thiocyanate, potassium cyanate, 2-cyanoacetamide and2-cyanoformamide, and in which the mole ratio of the organometalliccompound to the iron compound ranges from about 1/1 to about 4/1 and themolar ratio of the nitrogen ligand to the iron compound ranges fromabout 0.3/1 to about 3/1.
 3. A catalytic composition according to claim1 in which the iron containing compound is selected from the groupconsisting of iron octanote, iron decanoate, iron naphthenate and ferricacetylacetonate; the organometallic compound is selected from the groupconsisting of trialkylaluminums and dialkylaluminum hydrides; thenitrogen containing ligand is selected from the group consisting ofazobisisobutyronitrile, tetracyanoethylene, fumaronitrile andbutylthiocyanate; and the molar ratio of the organometallic compound tothe iron compound (Al/Fe) is from about 1/1 to about 12/1 and the molarratio of the nitrogen ligand to the iron compound (N/Fe) is from about0.1/1 to about 3/1.